Shunt resistance type current sensor

Abstract

A shunt resistance type current sensor includes a bus bar that is a path of an electric current to be measured, a circuit board that is installed over the bus bar, a pair of connecting members that electrically connect the circuit board with the bus bar, a voltage detection unit that is provided on the circuit board and detects a voltage value applied to the circuit board through the pair of connecting members so as to calculate a level of the electric current flowing through the bus bar, and a temperature sensor that is provided on the circuit board to face the bus bar and detects a temperature of the bus bar to allow the voltage detection unit to perform a correction regarding the calculation of the level of the electric current.

The invention claimed is: 
     
       1. A shunt resistance type current sensor comprising:
 a bus bar that is a path of an electric current to be measured; 
 a circuit board that is installed over the bus bar; 
 a pair of connecting members that electrically connect the circuit board with the bus bar; 
 a voltage detection unit that is provided on the circuit board and detects a voltage value applied to the circuit board through the pair of connecting members so as to calculate a level of the electric current flowing through the bus bar; and 
 a temperature sensor that is provided on the circuit board to face the bus bar and detects a temperature of the bus bar to allow the voltage detection unit to perform a correction regarding the calculation of the level of the electric current; 
 wherein the voltage detection unit includes a temperature detection portion for detecting the temperature of the bus bar, and determines an abnormality of the temperature sensor based on the temperature detected by the temperature detection portion and the temperature detected by the temperature sensor. 
 
     
     
       2. The shunt resistance type current sensor according to  claim 1 , wherein the voltage detection unit determines that the temperature sensor is abnormal, when a difference between the temperature detected by the temperature detection portion and the temperature detected by the temperature sensor is greater than a predetermined value. 
     
     
       3. The shunt resistance type current sensor according to  claim 1  further comprising a high thermal conductivity material that is disposed between the bus bar and the circuit board to thermally connect the bus bar and the circuit board.